Building blocks, in particular concrete building blocks, are used extensively in the construction of walls, both below grade in the case of foundation walls, and above grade, in the case of structural walls. Concrete blocks generally have hollow cores, planar, rectangular faces, and rectangular ends and upper and lower surfaces. They are ordinarily stacked in a stretching bond pattern, with mortar between each course of blocks, and between each block in a course. As required, rebar may be inserted in the cores of the blocks, after stacking, and the cores may be filled with concrete. There have, moreover, been attempts to develop concrete blocks with dry stacking capability. For instance, in U.S. Pat. No. 5,230,194 to McClure, a block is described with front and back faces that are offset slightly from the upper and lower surfaces, and the ends of the block. This feature permits the blocks to be dry stacked and interlocked. However, no satisfactory means for forming a corner is disclosed by McClure, who instead discloses an L-shaped corner suitable for one-way, right or left usage.
In U.S. Pat. No. 4,597,236 (Braxton), a dry-stack block is disclosed that relies on the use of spines insertable between blocks in a stacked wall. Braxton discloses corners constructed from blocks that are smaller than the remaining blocks in this system, and which do not permit the use of a stretcher bond pattern of block laying.
In view of the foregoing, the object of the present invention is to provide a novel dry stacking, interlocking concrete block that has a stretcher and corner embodiment of similar overall dimensions. Such a block can be utilized to dry stack a wall, with such corners as are desired by the builder rather than dictated by the block, in the traditional strong stretcher bond pattern of block laying.
A further object of the present invention is to provide a dry stack block that is provided with a surface that is grooved to permit fast and efficient drainage from the faces thereof.
In a broad aspect, then, the present invention relates to a building block comprising two substantially congruent rectangular panels joined together by at least one web extending transverse thereto, said panels having vertical end edges that are notched to interfit with the end edges of the panels of adjacent said blocks in a vertical joint therewith.